Different Types of Organic Molecules
The basic organic compound is the hydrocarbon. Hydrocarbons are compounds containing carbon and hydrogen atoms only. None are soluble in water, and all are flammable. Hydrocarbons are classified by the presence or absence of multiple bonds and/or a ring structure. They are the basis of which other, more complicated organic compounds are made, classified, and named. Different types of hydrocarbons include alkanes, cyclic alkanes, alkenes, and aromatics. Only a double bond between two carbon atoms and the orientation of the individual atoms make these otherwise identical molecules very different from each other.
Alkanes have a general formula of CnH2n+2 and have single carbon to carbon covalent bonds. All of the carbon atoms are surrounded by four single bonds, whether to other carbons or to other elements. An example of an alkane is ethane, C2H6. There is a single bond between the carbon atoms, and each carbon atom is surrounded by three hydrogen atoms.
Cycloalkanes have the general formula of CnH2n. Where alkanes have a chain structure, cycloalkanes are rings of carbon atoms. Cyclohexane, C6H12 is a good example of a cyclic alkane. It has a six member ring of carbon atoms, each bonded with two other atoms (hydrogen in this case).
Alkenes have the general formula of CnH2n and have carbon to carbon double bonds. Ethylene is an alkene because of the double bond between the two carbon atoms. Alkenes have very offensive odors.
Alkynes have the general formula of CnH2n-2 and have carbon to carbon triple bonds. Acetylene has a triple bond between the two carbon atoms, making it an alkyne.
Aromatics are rings of six carbon atoms with alternating single and double carbon to carbon covalent bonds. They are called aromatics because they have distinct smells to them. Benzene is an aromatic compound.
Through the use of addition and substitution reactions between these simple organic compounds, larger and more complicated molecules are formed such as the folowing. Adding bromine to ethylene produces 1,2-dibromoethane. Similarly, propene becomes propane when hydrogen gas is added. If the agent is hydrogen, as in this case, the process is called hydrogenation.
An alcohol is the result of one or more H atoms being replaced by an OH molecule in an alkane or an alkene. Methanol and ethanol are two common alcohols that are used in laboratories.
An aldehyde has one carbon double bonded to an oxygen atom and that same carbon is bonded to a hydrogen atom as well. Aldehydes are similar to organic acids, but are without the second oxygen atom. They are named by adding -al to the end of the common name, or by simply adding aldehyde to the end of the name.
Keytones are similar to aldehydes as in they have a carbon double bonded to an oxygen, but instead of being bonded to another hydrogen, the carbon is bonded to another carbon atom. These are named by adding -one to the end of the name, or by saying keytone at the end.
Carboxylic acids are the products of the oxidation of an alcohol and have a carbon doubly bonded to an oxygen atom, and singly bonded to an alcohol group. The strong taste of sourdough bread comes from carboxylic acids.
Esters are the addition of a carboxylic acid and an alcohol, with water as a byproduct. Esters are know for their sweet smells. The scent of pineapple is really the ester butyl butanoate. When an ester is broken down in the pressence of a strong base, usually NaOH, it becomes the salt of the origonal carboxylate acid and the origonal alcohol. This is sometimes called a saponification reaction because when a special type of ester is broken down, a fat,soap is produced.